Well completion equipment



March 12, 1963 Filed July 21, "1955 FIGJ M. P. LEBOURG WELL COMPLETION EQUIPMENT 2 Sheets-Sheet l INVENTOR. MAURICE P. LEBOURG.

W; mdhw HIS ATTORNEY.

March 12, 1963 M. P. LEBOURG WELL COMPLETION E UIPMENT 2 Sheets-Sheet 2 Filed July 21, 1955 jNVENTOR.

FIG.3

MAURICE F. LEBOURG.

HIS ATTORNEY.

United States Patent H 3,080,925 WELL CGMPLETION EQUIPMENT Maurice P. Lebourg, Houston, Tex., assignor, by mesne assignments, to Schlumberger Well Eurveying Corporation, Houston, Tex., a corporation of Texas Filed July 21, 1955, Ser. No. 523,495 Claims. (Cl. 166--236) This invention relates to systems for well production and completion and, more particularly, to production equipment for well completions wherein production tubing may remain indefinitely in a well.

After a well has been completed by conventional methods, the production tubing, for most workover operations, mustbe pulled from the well. In order to reduce the cost and time consumed in pulling production tubing, a technique has recently been devised wherein such tubing, once set, remains undisturbed in a well for an indefinite period, generally throughout the productive life of the well. This technique, known as permanent well completion, permits the productivity and productive life of a well to be extended by workover operations without requiring that the tubing be pulled from the well. As this permanent completion technique is now practiced, the bottom of the tubing string must be positioned at a fixed depth, which is usually a substantial distance above all formation zones that may subsequently be perforated. With such positioning, a perforating gun may be lowered beyond the bottom of the tubing to a point opposite a promising zone.

To facilitate operations performed on the well after the tubing has been set, nipples designed to seat a variety of wire line tools are commonly made up in the tubing string. Normally included is a landing nipple for seating an extension hanger. Whenever fluid circulation below the bottom of the tubing and at a point opposite a producing zone is desired, such extension hanger together with a dependently supported extension tube are run in through the tubing string and seated on this landing nipple. By facilitating fluid circulation at a point well beneath-the bottom of the tubing string, an extension tube makes possible such workover operations as washing sand from the bottom of a hole, squeeze cementing, and plug cutting, without requiring removal of the production tubing.

For other operations, however, tools and equipment must be placed at a point beneath the bottom of the tubing but are sized too large to pass through an extension tube. The bore of an extension tube, it will be understood, is substantially smaller than that of production tubing since the extension tube itself must pass through the production tubing. Consequently, equipment such as screens, landing nipples, packers and the like cannot be sized for making up in an extension tube and yet have as effective a functioning as full tubing-sized equipment.

For example, it is often desirable to position a screen opposite a producing sand formation to limit the extent of sanding in. Since the effectiveness of a screen depends on its close spacing to the casing wall, a screen sized to pass with an extension tube through the production tubing to a point therebeneath has only slight utility. As another example, a production packer is required to separate the flow from upper and lower zones in a dual completion.

For permanent dual completions, the present practice is to perforate the upper zone and then to run a tubing string in under pressure until its bottom reaches a point intermediate the two zones. This technique not only limits the production to zones of moderate pressure but also precludes workover operations upon the upper zone when the tubing is set. Properly speaking, therefore, the upper zone is not by this technique permanently completed.

Accordingly, it is an object of the present invention Patented Mar. 12, 1963 ice to provide new and improved well completion equipment by which the noted limitations in the above-described techniques may be overcome.

Another object of this invention is to provide new and improved well completion equipment whereby well flow devices of full tubing size or larger may be selectively positioned at points below the bottom of a tubing string.

Yet another object is to provide new and improved well completion equipment by which is an adjustment of the effective bottom depth of a production tubing string may be obtained without the introduction of an extension tube through the tubing string.

Still another object is to provide new and improved well production equipment which facilitates a permanent completion of, and separate production from plural producing zones of a well.

These and other objects are attained, in accordance with the invention, by coupling a terminal section of tubing to a tubing string for selective positioning telescopically about the lower portion of the tubing string or dependently therebelow. In order that the position of the terminal section may be changed without disturbing the tubing string, a selective coupling between the terminal sec tion and the tubing string is arranged for actuation by wire line operations.

In one instance, a screen for preventing sanding in at a producing zone is incorporated in the aforesaid terminal section. In an application of the invention to permanent completion of a dual flowing well, the terminal section is provided with a packer which may be set or released without manipulation of the tubing string selectively to pack off the producing zones.

Additional objects and advantages of the invention will become apparent from the following detailed description of a representative embodiment thereof, taken in conjunction with the drawings, in which:

FIG. 1 is an elevation, partly in section, depicting well completion equipment constructed in accordance with the present invention;

FIG. 1A is an elevation of an outer wall portion of the equipment taken along lines AA of FIG. 1;

FIG. 2 is an elevation, similar to FIG. 1, showing the terminal section in its lowered position;

FIG. 2A is an elevation of a sleeve shifting tool;

FIG. 3 is an elevation, partly in section, illustrating a system for permanent dual completions in accordance with a modification of the present invention including a latching structure schematically shown;

FIG. 3A is an elevation of a tubing plug;

FIG. 4 is an elevation, similar to FIG. 3, illustrating a production packer set in the lowered position of the terminal section including a latching structure schematically shown.

Throughout the drawings, like reference numerals are employed to designate similar parts.

In FIG. 1 there is shown a well 10 extending through formations 11, including a pay zone 12, such as an unconsolidated oil sand horizon. A casing 14 set along the length of the well 10 to close off the formations 11 has connected at its upper end well head apparatus (not shown) of any suitable type. Supported by this well head apparatus is a string 15 of production tubing joints or sections 16 extending through the casing 14 to a point spaced above the producing zone 12. In the usual case, joints 16 made up in the tubing string have a generally uniform bore diameter on the order of 2 or 2 /2 inches.

Before the zone 12 is brought into production, the well 10 is loaded with weighting fluid 2.0, such as salt water, to achieve a desired hydrostatic head opposing influx of formation fluids. The Weighting fluid 2% is separated by the tubing string 15 into a column 21 extending to the surface and into a coextensive annulus 22, such alleviating a sanding-in problem.

bombs, perforating guns, and the like.

- tubing string.

To attain the objectives of this invention, the coupling 26 has fitted telescopically about it a terminal tubing section 36 which may be extended selectively to depths below the bottom of the tubing string. As seen in FIG. 1, the terminal section is in its upper raised position overlying not only the coupling 26 but also the tubing plug nipple 27 and a portion of the tubing joint 16. Conveniently, the terminal section 36 comprises a plurality of joints 31, 32 as well as a tubular device 34 which is to be selectively fixed in raised and lowered positions. In the embodiment of the invention shown in FIGS. 1 and 2, the device 34 is a screen having the purpose of Preferably, the device or screen 34 has a bore 35 throughout its length at least sufficiently large to pass the conventional wire line tools (not shown) such as running and pulling tools, pressure Consequently, the screen 34 may be referred to as being of full tubing size.

The coupling 26, which serves to guide and selectively retain the terminal section 36, comprises a tubular portion 40 defining a main cylindrical bore 41 conforming in diameter to the remainder of the tubing string 15. Intermediate the cnds of the tubular portion 40 is an enlarged section 46 having a diameter which is slightly less than the diameter of the bore of joints 31 and 32. Thus, the enlarged section 46 serves to guide the terminal section 30 for relative longitudinal movement on the coupling 26.

In the enlarged section 46 are elongated slots or recesses 59 and 69 (see FIG. 1A) which are longitudinally aligned and spaced from one another. The bore 41 is provided with an internal annular recess 42 (FIG. 1) which lies intermediate of the respective lower and upper ends of slots 59 and 69. An upper portion of the recess 42 opens into the lower portion of slot 69 while a lower portion of the recess 42 opens into the upper portion of slot 59, the recess having opposed upper and lower shoulders 43 and 44. A leaf spring 64 is disposed in slot 69 and has a base portion suitably secured to the upper end surface of the slot, for example, by welding, and a substantially fiat portion extending longitudinally of the slot with a hooked end portion 63 which, in its normally unbiased condition, tends to extend inwardly into the opening formed by the lower end portion of the slot 69 and internal recess 42. Similarly, a leaf spring 54 is provided for slot 59 and suitably secured to the lower end surface of slot 59, the spring 54 having configuration similar to spring 64. In FIG. 1, spring 54 is shown in a biased condition with the hooked end portion 53 displaced outwardly from the opening formed by the upper end portion of slot 59 and the internal recess 42.

To effect movement of the springs from their unbiased to biased conditions, a tubular locking sleeve 47 is provided within the bore 41. The locking sleeve 47 has upper and lower portions e812, 4852 sized to be slidably received within bore 41 and an intermediate enlarged portion 48 extending into recess 42. The width of enlarged portion 48 is less than the width of the recess 42 so that enlarged portion 48, when in a lower position, abuts shoulder 44 and the opening of the lower portion of slot 6% is unblocked from enlarged portion 48 of the sleeve 47 thereby permitting the hooked end portion 63 of spring 64 to lie within the opening. Upon movement of the locking sleeve 47 in an upward direction, the upper end of enlarged portion 48 engages the hooked end portion 63 camming it outwardly to a biased condition while the lower end of the enlarged portion 48 unblocks the opening between the upper portion of slot 59 and recess 42 permitting the spring 54 to return to an unbiased condition (see FIG. 2). As the sleeve 47 has a bore 69 smaller in diameter than bore 41, it may be engaged by a conventional sleeve shifting tool 47A, for example, of the type illustrated in the Patent No. 2,155,620 to D. Scararnucci as shown in FIG. 2A, for movement from a lower to an upper locking position. For movement of the locking sleeve 47 from its upper to its lower locking positions, there may be used, for example, a conventional cylindrical mandrel, adapted to be lowered on a wire line and having a diameter greater than the bore 60 of the locking sleeve 47 but less than the bore 41 of the coupling 26 and the bore of the tubing string 15 and having sufiicient weight to overcome the locking action of the spring ring '50.

To releasably retain the locking sleeve '47 in the upper and lower positions above described, the outer surface of the enlarged portion 48 of the locking sleeve 47 is provided with a circumferential groove 49 containing an expansible spring ring 50 and the wall surface of recess 42 in the tubular portion 49 is provided with longitudinally spaced, circumferential grooves 51, 52. The spring ring 50 is normally extended outwardly into either groove 51 or 52 dependent upon the position of sleeve 47 andretracts entirely into groove 52 when the locking sleeve 47 is moved between the lower to the upper positions.

To latch the terminal section 30 in its upper and lower positions relative to coupling 26, the joints 31 and 32 are provided with annular grooves 68 and 58 which respectively receive the latches 65 and 55 mounted on the tubular portion 40. Groove 68 has a shoulder facing downwardly while groove 58 has a shoulder facing upwardly, the-grooves being spaced longitudinally from one another. Latch 65 is an elongated member having an end portion adjacent to the base portion of the leaf -spring 64- and it is pivotally mounted to the tubular portion 40 by a pin 66. The mid-point of the latch 65 is secured to the spring 64, for example, by welding. Similarly, latch 55 is an elongated member with an end portion disposed adjacent to the base portion of spring 54 and pivotally mounted to the tubular portion 49 by a pin 56. The mid-point of latch 55 is secured to spring 54, for example, by welding. The unsecured remaining end portions 57, 67 of latches 55 and 65 face one another and are adapted to extend outwardly to respectively engage the grooves 58 and 68. Thus, each of the latches 55 and 65 is observed to providea unidirectional locking action and to be biased by the respective leaf springs 54, 64 out of locking engagement with the terminal section 30 dependent upon the respective position of sleeve Terminal section 30, at its upper end has a downwardly and inwardly facing shoulder 61 formed on an enlarged upper end of its joint 31 while enlarged portion 40 has an upwardly and outwardly directed shoulder 62, the shoulders 61, 62 serving to support terminal section 30 in its lowermost position as shown in FIG. 2. For many applications the weight of the terminal section 30 is sufiicient to hold the section in its lowermost position so that the latch member 65 may not be necessary.

O-rings 70 set in the bore 41 of the coupling 26 are in sealing engagement with the sleeve 47 to close ofi the slots 59, 69 from the bore 41 of the coupling 26. It is also desirable to seal the lower ends of tubing string 15 and terminal section 30 when the latter is raised. To this end the screen 34, as illustrated in FIGS. 1 and 2, has an inwardly and upwardly directed shoulder 71 disposed intermediate an enlarged slotted screen portion 72 and a reduced nipple portion 73. In the raised position of the terminal section 30, this shoulder 71 is in abutment with an outwardly and downwardly directed shoulder 74 of the expendable tubing plug nipple 27.

The'shoulder 74 is provided with an annular groove 75 receiving an O-ring seal 76 for sealing with the shoulder 71. In the raised position of the terminal section 30, then, the tubing string 15 and terminal section 30 together may be fluid tight down to the nipple portion 73 of the screen 34. An expendable tubing plug 45 as shown in FIG. 3A, of the type described on page 3989, vol. 2 of the Composite Catalog of Oil Field and Pipeline Equipment, 20th ed., 1954-1955, published by World Oil, may therefore be landed in the nipple portion 73 of the screen to close off the tubing string 15. To make this possible, the bore 35 of the nipple portion 73 is somewhat smaller than the bore 60 of the sleeve 47. Noteworthy is the fact that the screen portion 72 is of even larger diameter than would be a conventional screen afiixed at the end of the tubing string 15, with a result that the screen portion 72 is adapted more effectively to prevent sanding in.

In the technique of permanent completion for which the well completion equipment of this invention is particularly suited, the tubing string 15 is run into the cased well with the terminal section 30 locked in its raised position. The locking sleeve 47 is thus in its lowered position. When the bottom ends of both the tubing string and the terminal section 30 are spaced above the pay zone '12 with a sufiicient clearance for perforating operations, the tubing string is set by installation of well head equipment. A perforating tool (not shown) is lowered through the tubing string 15 into weighting liquid to perforate the casing 14 opposite the pay zone 12 and is then withdrawn. Due to the hydrostatic pressure provided by the weighting liquid 20, premature production from the zone 12 is forestalled.

A suitable sleeve shifting tool is then introduced for engaging the locking sleeve 47 and shifting it to its raised position. In the upper position of the locking sleeve 47, the outer peripheral surface of the enlarged portion 48 actsupon camming end 63 of the leaf spring 64 to urge the detent 65 resiliently against the interior wall of the terminal section 33. At the same time, the detent 55 is freed for withdrawal from groove 58 in which it was engaged to resist downward movement of the terminal section 30. Thus, gravity will cause the terminal section 39 to drop to its lowermost position. In the event that the force of gravity is insufficient to accomplish this, a suitable tool (not shown) may be landed in the nipple portion "/3 of the screen 34 and jarred downwardly by wire line operations to cause the terminal section to fall to its desired position,

In the extended position of the terminal section 30', as seen in FIG. 2, the screen portion 72 is directly opposite the pay zone 12 and in close proximity to it by reason of the enlarged diameter of the screen portion 72 relative to the outside diameter of the tubing string 15. If desired, the bore 35' through the nipple portion 73 of the screen could be closed by an expendable tubing plug 45, as shown in FIG. 3A so that flow of fluids from the zone 12 into the tubing string would be exclusively through the slotted screen portion 72. Despite a substantial pressure differential across the screen portion 72, the terminal section 30 will not be forced upwardly due to engagement of the detent 65 in the annular groove 68.

Whenever workover operations on the producing zone 12 are to be undertaken, the terminal section 30 is raised by engagement of a suitable wire line tool with the nipple portion 73 after shifting the locking sleeve 47 into its lowered position. Not only does lowering of the locking sleeve 47 free the terminal section 30 for upward movement, but also it ensures that the terminal section will be retained in its uppermost position by detent 55 when that position is reached.

In lieu of the screen 34, there can be coupled to the terminal section other tubular devices which may usefully be positioned a selected distance beneath the bottom of the tubing string. For example, a landing nipple of 6 the type described in Miller Patent No. 2,673,614, issued March 30, 1954 may be employed to receive a variety of flow control devices.

Where the well to be completed includes two or more zones, as are illustrated in FIGS. 3 and 4, a packer 30 may be carried by the terminal section in lieu of the screen 34. This packer 89 generally comprises a tubular body carrying a resilient packing element, means for forcing the packing element outwardly, and slips for holding the packer in a set condition. A suitabl releasible packer is shown in copending application Serial No. 512,108 filed May 31, 1955, now Patent No. 2,842,212, by M. Lebourg and assigned to the assignee hereof. For a permanent completion of dual zones, such as an upper gas sand 81 and a lower oil sand 82, the packer is p hsitioned above the upper zone 81 a suflicient distance to permit perforating operations. In order that the packer may be set intermediate the zones 81, 82 after the upper zone 81 has been perforated, an additional one or more joints 84 in the terminal section 30 may be necessary.

In FIG. 3 is shown a perforating tool 85 suspended by cable 86 opposite the upper zone 8-1. The perforating tool 85 is shown opposite the lower Zone '82 when the packer 80 has been set intermediate the zones 81, 82. Setting of packer 80 may be accomplished by a suitable setting tool such as that shown in above-mentioned application Serial No. 512,108. In other respects, the well completion equipment of FIGS. 3 and 4 is identical with that of FIGS. 1 and 2.

In employing the well completion equipment of FIGS. 3 and 4 for a permanent dual completion, the tubing string 15 is introduced into the cased well 10 with the terminal section 3% retracted. When packer 80 is spaced a distance above the upper zone 81 sufiicient for perforating operation, the tubing string is set. The perforating tool 85 is then run into a position opposite zone 81, is energized to perforate the casing 14 opposite such zone, and then withdrawn. Thereupon, a suitable sleeve shifting tool 47A, as shown in FIGURE 2A is introduced to release the terminal section 30 for movement to its extended position. By a proper selection of the joints 31, 32 and 84 their length will carry the packer 89 to a position intermediate the zones 81, 82. With the packer 80 held in this intermediate position by the terminal section '30, the sleeve shifting tool is replaced by the packer setting tool. By energization of this setting tool the slips of the packer 80 are set against the casing 14 to lock the packing element in sealed relation to the casing. Thus, the upper zone 81 is readied for production through the casing annulus 22.

To perforate the lower zone 32, the perforating tool 85 is again introduced through the tubing string and is positioned opposite this lower zone 32. After energization to perforate the casing 14 opposite this lower zone 82, the perforating tool 85 is withdrawn from the well. The lowered zone 82 is then ready to be brought into production.

By employing a packer $0 which is releasible by a wire line tool, workover operations may be conducted not only on the lower zone 82 which is below the packer 80 but also upon the upper zone 81 above the packer. This is accomplished by squeezing off the lower zone 82, if necessary, and then releasing the packer 86.. Thereupon, the terminal section St is raised to its uppermost locking position whereupon workover operations may be freely conducted upon the upper zone 31.

If desired, provision may be made at a suitable poin in the tubing string 15 for selective crossover flow in any suitable manner whereby selective production either through the tubing string or the casing annulus may be had with the well completion equipment of this invention. This crossover fiow is particularly desirable, for example, where the zones 81, 82 are both productive of oil and have producing characteristics which vary over the life of the well.

Sinceneither the'upper nor the lower zone is perforated until after the tubing string has been set, and then all subsequent operations are performed by wire line or cable which may be readily introduced through a conventional well head stuffing box (not shown), it will be evident that this system for dual completion may be employed even with abnormally high pressure formations. Where the formations have an insufiicient pressure to flow naturally, on the other hand, artificially assisted production either by gas lifting or by pump landed in the bore of the packer 84) might be effectively utilized.

Or" the variety of packers and setting tools which may satisfactorily be utilized, those in which both setting and releasing may be accomplished without imposing substantial loads upon the tubing string or terminal section are preferred. It will be understood, then, that embodiments of the invention illustrated and described herein are merely exemplary and are subject to many modifications in addition to those described above. These embodiments of the invention are therefore not to be taken as limitations upon the invention but as exemplifying its spirit and principles, its scope being defined in the appended claims.

I claim:

1. Apparatus for extending the lower end of a tubing string in a well comprising: a tubular member having at least one of its ends threaded for connecting said member in'a tubing string adjacent the fixed lower end thereof, said member having a continuous bore extending therethrough substantially conforming in diameter to said tubing string and an exterior portion enlarged with respect to said tubing String defining an upwardly directed shoul der; a terminal tubing section telescopically received about said tubular member for sliding movement between a retracted position and an extended position and dependently supported in said extended position by said shoulder to define an extended open lower end of the passageway through said tubing string; latch means for releasably locking said terminal tubing section in at least one of said positions including a latch member in an open- .ing in said tubular member, said latch member arranged to retract into and extend outwardly from said tubular member, said terminal tubing section having its interior cooperable with said latch member, a tubular sleeve slidably mounted in said tubular member, said tubular sleeve having a bore of slightly less diameter than the string of tubing located adjacent said opening, and means on said tubular sleeve to control movement of said latch member between a retracted and extended condition.

2. Apparatus as defined in claim 1, wherein said terminal tubing section has a reduced bore portion at its lower end to define an upwardly directed interior shoulder engageable with the lower end of said tubular member; and means for effecting an annular seal between the lower end of said tubular member and the upwardly directed shoulder of said terminal section in the retracted position thereof.

3. Apparatus as defined in claim 1 wherein said terminal tubing section is of a length to extend a substantial distance above and below said tubular member when in its retracted position; and packer means carried by the portion of said terminal section below said tubular member arranged to be expanded into set position.

4. The apparatus as defined in claim 2 wherein said terminal tubing section has openings therein to form a screen.

5. Apparatus for extending the lower end of a tubing string in a well, comprising a tubular coupling member having at least one of its ends threaded for connecting said member in a tubing string adjacent the fixed lower end thereof, said member having a continuous bore extending therethrough conforming substantially in diameter to said tubing string and an annular recess along .said bore, a sleeve slidably retained in said recess and projecting into said bore a slight distance to be engageable .tor movement between two positions, a terminal tubing section telescopically slidable over said coupling member between an extended and a retracted position variably to extend the lower end of said tubing string, means to support said terminal section on said tubular coupling member in the extended position, and means carried by said coupling member for releasably latching said terminal section in a position determined by the position .of said sleeve.

6. The apparatus as defined in claim 5 wherein said terminal tubiat section has openings therein to form a screen and meansfor sealing said terminal tubing section relative to said tubular coupling member in said retracted position of said terminal tubing section.

7. The apparatus as defined in claim 5 wherein said terminal tubing section has openings therein to form a screen and wherein the lower end of said terminal tubing section has a reduced diameter to define an upwardly directed interior shoulder engageable with the lower end of said tubular coupling member; and means for effecting an annular seal between the lower end of said tubular coupling member and the upwardly directed shoulder of said terminal tubing sectionv in the retracted position.

8. The apparatus as defined in claim 5 wherein the lower end of said terminal tubing section has a reduced diameter to define an upwardly directed interior shoulder engagcable with the lower end of said tubular coupling member; and means for effecting an annular seal between the lower end of said tubular coupling member and the upwardly directed shoulder of said terminal tubing section in the retracted position.

9. For use with oil production equipment, the combination comprising: a tubular coupling member having one'endadapted for connection with a string of tubing and having a bore of substantially the same diameter as the string of tubing; a terminal tubing section telescopically received over the other end of said tubular coupling member and movable between spaced longitudinal positions on said tubular coupling member; latch means for releasably locking said terminal tubing section in at least one of said positions including a latch member on said tubular coupling member arranged to retract into and extend outwardly from said tubular coupling member, said terminal tubing section having a grooved interior cooperable with said latch member, said tubular coupling member having an opening to said internal recess, means to mount said latch member in said opening, a tubular sleeve slidably mounted in said bore of said tubular coupling member, said tubular sleeve having a bore of slightly less diameter than the string of tubing, said tubular sleeve further having an enlarged portion received by said internal recess, said enlarged portion cooperable with said latch member to control movement of said latch member between a retracted and extended condition.

10. 'For use with oil production equipment, the combination comprising: a tubular coupling member having one end adapted for connection with a string of tubing and having a bore of substantially the same diameter as the string of tubing; a terminal tubing section telescopically received over said tubular coupling member and movable between spaced longitudinal positions on said tubular coupling member; latch means for releasably locking said terminal tubing section in at least one of said positions including a latch member on said tubular coupling member arranged to retract into and extend outwardly from said tubular coupling member, said terminal tubing section having a grooved interior coopcrable with said latch member, said tubular coupling member having an internal recess, said tubular coupling member further having an opening to said internal recess, means to mount said latch member in said opening, means to resiliently bias said latch member towards a retracted condition, a tubular sleeve slidably mounted insaid bore References Cited in the file of this patent UNITED STATES PATENTS 1,944,443 Manning n Jan. 23, 1934 Pattens-on July 7, 1936 10 Henderson Oct. 15, 1940 Collins et a1. Oct. 3, 1944 Barnes Dec. 19, 1944 Orr Mar. 26, 1946 Hart et a1. Nov. 13, 1951 Pletcher Mar. 18, 1952 Baker et a1. Mar. 6, 1956 Tausch et al. Feb. 26, 1957 Kanady Mar. 5, 1957 McCulloch May 27, 1958 

1. APPARATUS FOR EXTENDING THE LOWER END OF A TUBING STRING IN A WELL COMPRISING: A TUBULAR MEMBER HAVING AT LEAST ONE OF ITS ENDS THREADED FOR CONNECTING SAID MEMBER IN A TUBING STRING ADJACENT THE FIXED LOWER END THEREOF, SAID MEMBER HAVING A CONTINUOUS BORE EXTENDING THERETHROUGH SUBSTANTIALLY CONFORMING IN DIAMETER TO SAID TUBING STRING AND AN EXTERIOR PORTION ENLARGED WITH RESPECT TO SAID TUBING STRING DEFINING AN UPWARDLY DIRECTED SHOULDER; A TERMINAL TUBING SECTION TELESCOPICALLY RECEIVED ABOUT SAID TUBULAR MEMBER FOR SLIDING MOVEMENT BETWEEN A RETRACTED POSITION AND AN EXTENDED POSITION AND DEPENDENTLY SUPPORTED IN SAID EXTENDED POSITION BY SAID SHOULDER TO DEFINE AN EXTENDED OPEN LOWER END OF THE PASSAGEWAY THROUGH SAID TUBING STRING; LATCH MEANS FOR RELEASABLY LOCKING SAID TERMINAL TUBING SECTION IN AT LEAST ONE OF SAID POSITIONS INCLUDING A LATCH MEMBER IN AN OPENING IN SAID TUBULAR MEMBER, SAID LATCH MEMBER ARRANGED TO RETRACT INTO AND EXTEND OUTWARDLY FROM SAID TUBULAR MEMBER, SAID TERMINAL TUBING SECTION HAVING ITS INTERIOR COOPERABLE WITH SAID LATCH MEMBER, A TUBULAR SLEEVE SLIDABLY MOUNTED IN SAID TUBULAR MEMBER, SAID TUBULAR SLEEVE HAVING A BORE OF SLIGHTLY LESS DIAMETER THAN THE STRING OF TUBING LOCATED ADJACENT SAID OPENING, AND MEANS ON SAID TUBULAR SLEEVE TO CONTROL MOVEMENT OF SAID LATCH MEMBER BETWEEN A RETRACTED AND EXTENDED CONDITION. 